1
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Forget S, Juillé M, Duboué-Dijon E, Stirnemann G. Simulation-Guided Conformational Space Exploration to Assess Reactive Conformations of a Ribozyme. J Chem Theory Comput 2024; 20:6263-6277. [PMID: 38958594 DOI: 10.1021/acs.jctc.4c00294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Self-splicing ribozymes are small ribonucleic acid (RNA) enzymes that catalyze their own cleavage through a transphosphoesterification reaction. While this process is involved in some specific steps of viral RNA replication and splicing, it is also of importance in the context of the (putative) first autocatalytic RNA-based systems that could have preceded the emergence of modern life. The uncatalyzed phosphoester bond formation is thermodynamically very unfavorable, and many experimental studies have focused on understanding the molecular features of catalysis in these ribozymes. However, chemical reaction paths are short-lived and not easily characterized by experimental approaches, so molecular simulation approaches appear as an ideal tool to unveil the molecular details of the reaction. Here, we focus on the model hairpin ribozyme. We show that identifying a relevant initial conformation for reactivity studies, which is frequently overlooked in mixed quantum-classical studies that predominantly concentrate on the chemical reaction itself, can be highly challenging. These challenges stem from limitations in both available experimental structures (which are chemically altered to prevent self-cleavage) and the accuracy of force fields, together with the necessity for comprehensive sampling. We show that molecular dynamics simulations, combined with extensive conformational phase space exploration with Hamiltonian replica-exchange simulations, enable us to characterize the relevant conformational basins of the minimal hairpin ribozyme in the ligated state prior to self-cleavage. We find that what is usually considered a canonical reactive conformation with active site geometries and hydrogen-bond patterns that are optimal for the addition-elimination reaction with general acid/general base catalysis is metastable and only marginally populated. The thermodynamically stable conformation appears to be consistent with the expectations of a mechanism that does not require the direct participation of ribozyme residues in the reaction. While these observations may suffer from forcefield inaccuracies, all investigated forcefields lead to the same conclusions upon proper sampling, contrasting with previous investigations on shorter timescales suggesting that at least one reparametrization of the Amber99 forcefield allowed to stabilize aligned active site conformations. Our study demonstrates that identifying the most pertinent reactant state conformation holds equal importance alongside the accurate determination of the thermodynamics and kinetics of the chemical steps of the reaction.
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Affiliation(s)
- Sélène Forget
- PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, 75005 Paris, France
| | - Marie Juillé
- PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, 75005 Paris, France
- Université Paris Cité, CNRS, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Elise Duboué-Dijon
- Université Paris Cité, CNRS, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Guillaume Stirnemann
- PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, 75005 Paris, France
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2
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Platnich CM, Earle MK, Keyser UF. Chemical Annealing Restructures RNA for Nanopore Detection. J Am Chem Soc 2024; 146:12919-12924. [PMID: 38691627 PMCID: PMC11099964 DOI: 10.1021/jacs.4c03753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/03/2024]
Abstract
RNA is a key biochemical marker, yet its chemical instability and complex secondary structure hamper its integration into DNA nanotechnology-based sensing platforms. Relying on the denaturation of the native RNA structure using urea, we show that restructured DNA/RNA hybrids can readily be prepared at room temperature. Using solid-state nanopore sensing, we demonstrate that the structures of our DNA/RNA hybrids conform to the design at the single-molecule level. Employing this chemical annealing procedure, we mitigate RNA self-cleavage, enabling the direct detection of restructured RNA molecules for biosensing applications.
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Affiliation(s)
- Casey M. Platnich
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Max K. Earle
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Ulrich F. Keyser
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
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3
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Chen CC, Han J, Chinn CA, Rounds JS, Li X, Nikan M, Myszka M, Tong L, Passalacqua LFM, Bredy T, Wood MA, Luptak A. Inhibition of Cpeb3 ribozyme elevates CPEB3 protein expression and polyadenylation of its target mRNAs and enhances object location memory. eLife 2024; 13:e90116. [PMID: 38319152 PMCID: PMC10919898 DOI: 10.7554/elife.90116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 02/05/2024] [Indexed: 02/07/2024] Open
Abstract
A self-cleaving ribozyme that maps to an intron of the cytoplasmic polyadenylation element-binding protein 3 (Cpeb3) gene is thought to play a role in human episodic memory, but the underlying mechanisms mediating this effect are not known. We tested the activity of the murine sequence and found that the ribozyme's self-scission half-life matches the time it takes an RNA polymerase to reach the immediate downstream exon, suggesting that the ribozyme-dependent intron cleavage is tuned to co-transcriptional splicing of the Cpeb3 mRNA. Our studies also reveal that the murine ribozyme modulates maturation of its harboring mRNA in both cultured cortical neurons and the hippocampus: inhibition of the ribozyme using an antisense oligonucleotide leads to increased CPEB3 protein expression, which enhances polyadenylation and translation of localized plasticity-related target mRNAs, and subsequently strengthens hippocampal-dependent long-term memory. These findings reveal a previously unknown role for self-cleaving ribozyme activity in regulating experience-induced co-transcriptional and local translational processes required for learning and memory.
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Affiliation(s)
- Claire C Chen
- Department of Pharmaceutical Sciences, University of California, IrvineIrvineUnited States
| | - Joseph Han
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, IrvineIrvineUnited States
| | - Carlene A Chinn
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, IrvineIrvineUnited States
| | - Jacob S Rounds
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, IrvineIrvineUnited States
| | - Xiang Li
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, IrvineIrvineUnited States
| | | | - Marie Myszka
- Department of Chemistry, University of California, IrvineIrvineUnited States
| | - Liqi Tong
- Institute for Memory Impairments and Neurological Disorders, University of California, IrvineIrvineUnited States
| | - Luiz FM Passalacqua
- Department of Pharmaceutical Sciences, University of California, IrvineIrvineUnited States
| | - Timothy Bredy
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, IrvineIrvineUnited States
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, IrvineIrvineUnited States
| | - Andrej Luptak
- Department of Pharmaceutical Sciences, University of California, IrvineIrvineUnited States
- Department of Chemistry, University of California, IrvineIrvineUnited States
- Department of Molecular Biology and Biochemistry, University of California, IrvineIrvineUnited States
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4
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Wang Z, Cheng J, Dai G, Sun X, Yin X, Zhang Y. The Establishment of a Tobramycin-Responsive Whole-Cell Micro-Biosensor Based on an Artificial Ribozyme Switch. Life (Basel) 2023; 13:1553. [PMID: 37511928 PMCID: PMC10381313 DOI: 10.3390/life13071553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/25/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
In this study, a tobramycin concentration-dependent whole-cell micro-biosensor (tob-HHAz) was constructed by fusing a tobramycin aptamer with a hammerhead ribozyme (HHR) from Schistosoma mansoni. The biosensor was obtained by integrating all the modules into one complete RNA sequence, which was easily introduced into E. coli without suffering from harsh external environments. Three independent tobramycin-sensitive RNA structures were identified via high-throughput screening in vivo and were further verified in vitro to undergo the desired self-cleavage reaction. The computation prediction of the RNA structure was performed to help analyze the mechanisms of various conformations by performing a qualitative and rapid detection of tobramycin in practical samples; two sensors exhibited high responsiveness to spiked milk, with a detection limit of around 40 nM, which is below the EU's antibiotic maximum residual level. One of the structures provides a linear range from 30 to 650 nM with a minimum detection limit of 30 nM and showed relatively good selectivity in spiked urine. This study is the first in which in vivo screening was combined with computation analysis to optimize the pivotal structure of sensors. This strategy enables researchers to use artificial ribozyme-based biosensors not only for antibiotic detection but also as a generally applicable method for the further detection of substances in living cells.
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Affiliation(s)
- Zhenzhen Wang
- School of Life Science, Anhui Medical University, Hefei 230032, China
| | - Jiawen Cheng
- School of Life Science, Anhui Medical University, Hefei 230032, China
| | - Guimin Dai
- School of Life Science, Anhui Medical University, Hefei 230032, China
| | - Xiaoqi Sun
- School of Life Science, Anhui Medical University, Hefei 230032, China
| | - Xueli Yin
- School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Yuanyuan Zhang
- School of Life Science, Anhui Medical University, Hefei 230032, China
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5
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Chen CC, Han J, Chinn CA, Rounds JS, Li X, Nikan M, Myszka M, Tong L, Passalacqua LFM, Bredy TW, Wood MA, Lupták A. Inhibition of CPEB3 ribozyme elevates CPEB3 protein expression and polyadenylation of its target mRNAs, and enhances object location memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.543953. [PMID: 37333407 PMCID: PMC10274809 DOI: 10.1101/2023.06.07.543953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
A self-cleaving ribozyme that maps to an intron of the cytoplasmic polyadenylation element binding protein 3 (CPEB3) gene is thought to play a role in human episodic memory, but the underlying mechanisms mediating this effect are not known. We tested the activity of the murine sequence and found that the ribozyme's self-scission half-life matches the time it takes an RNA polymerase to reach the immediate downstream exon, suggesting that the ribozyme-dependent intron cleavage is tuned to co-transcriptional splicing of the CPEB3 mRNA. Our studies also reveal that the murine ribozyme modulates maturation of its harboring mRNA in both cultured cortical neurons and the hippocampus: inhibition of the ribozyme using an antisense oligonucleotide leads to increased CPEB3 protein expression, which enhances polyadenylation and translation of localized plasticity-related target mRNAs, and subsequently strengthens hippocampal-dependent long-term memory. These findings reveal a previously unknown role for self-cleaving ribozyme activity in regulating experience-induced co-transcriptional and local translational processes required for learning and memory.
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Affiliation(s)
- Claire C. Chen
- Department of Pharmaceutical Sciences, University of California–Irvine, Irvine, California 92697, United States
| | - Joseph Han
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, United States
| | - Carlene A. Chinn
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, United States
| | - Jacob S. Rounds
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, United States
| | - Xiang Li
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, United States
| | - Mehran Nikan
- Ionis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Marie Myszka
- Department of Chemistry, University of California–Irvine, Irvine, California 92697, United States
| | - Liqi Tong
- Institute for Memory Impairments and Neurological Disorders, University of California–Irvine, Irvine, California 92697, United States
| | - Luiz F. M. Passalacqua
- Department of Pharmaceutical Sciences, University of California–Irvine, Irvine, California 92697, United States
| | - Timothy W. Bredy
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, United States
| | - Marcelo A. Wood
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, United States
| | - Andrej Lupták
- Department of Pharmaceutical Sciences, University of California–Irvine, Irvine, California 92697, United States
- Department of Chemistry, University of California–Irvine, Irvine, California 92697, United States
- Department of Molecular Biology and Biochemistry, University of California–Irvine, Irvine, California 92697, United States
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6
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Mao S, Tsai HC, Sheng J. Synthesis of 5-Cyanomethyluridine (cnm 5 U) and 5-Cyanouridine (cn 5 U) Phosphoramidites and Their Incorporation into RNA Oligonucleotides. ACTA ACUST UNITED AC 2021; 82:e114. [PMID: 32846053 DOI: 10.1002/cpnc.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This article contains detailed synthetic protocols for preparation of 5-cyanomethyluridine (cnm5 U) and 5-cyanouridine (cn5 U) phosphoramidites. The synthesis of the cnm5 U phosphoramidite building block starts with commercially available 5-methyluridine (m5 C), followed by bromination of the 5-methyl group to install the cyano moiety using TMSCN/TBAF. The cn5 U phosphoramidite is obtained by regular Vorbrüggen glycosylation of the protected ribofuranose with silylated 5-cyanouracil. These two modified phosphoramidites are suitable for synthesis of RNA oligonucleotides on solid phase using conventional amidite chemistry. Our protocol provides access to two novel building blocks for constructing RNA-based therapeutics. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Preparation of cnm5 U and cn5 U phosphoramidites Basic Protocol 2: Synthesis, purification, and characterization of cnm5 U- and cn5 U-modified RNA oligonucleotides.
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Affiliation(s)
- Song Mao
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, New York
| | - Hsu-Chun Tsai
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, New York
| | - Jia Sheng
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, New York
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7
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Chakraborty D, Ghosh S. Demonstration of a Ribozyme in Epsilon Domain of Hepatitis B Virus RNA. Methods Mol Biol 2021; 2167:45-59. [PMID: 32712914 DOI: 10.1007/978-1-0716-0716-9_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The epsilon domain of Hepatitis B virus plays a crucial role in encapsidation of viral pregenomic RNA and its partial NMR structure has been determined. However, we recently described a potassium-dependent ribonucleolytic activity associated with this region, so that a 53 nt long RNA containing the epsilon domain could release itself and cleaved other RNAs. We describe here the experimental methodologies for setting up the reactions and outline a general strategy for initial demonstration of this self-cleaving ribozyme activity.
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Affiliation(s)
| | - Sagarmoy Ghosh
- Department of Microbiology, University of Calcutta, University College of Science and Technology, Kolkata, India.
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8
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Abstract
Self-cleaving ribozymes are RNA molecules that catalyze a site-specific self-scission reaction. Analysis of self-cleavage is a crucial aspect of the biochemical study and understanding of these molecules. Here we describe a co-transcriptional assay that allows the analysis of self-cleaving ribozymes in different reaction conditions and in the presence of desired ligands and/or cofactors. Utilizing a standard T7 RNA polymerase in vitro transcription system under limiting Mg2+ concentration, followed by a 25-fold dilution of the reaction in desired conditions of self-cleavage (buffer, ions, ligands, pH, temperature, etc.) to halt the synthesis of new RNA molecules, allows the study of self-scission of these molecules without the need for purification or additional preparation steps, such as refolding procedures. Furthermore, because the transcripts are not denatured, this assay likely yields RNAs in conformations relevant to co-transcriptionally folded species in vivo.
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9
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Novikov IB, Wilkins AD, Lichtarge O. An Evolutionary Trace method defines functionally important bases and sites common to RNA families. PLoS Comput Biol 2020; 16:e1007583. [PMID: 32208421 PMCID: PMC7092961 DOI: 10.1371/journal.pcbi.1007583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 11/27/2019] [Indexed: 11/18/2022] Open
Abstract
Functional non-coding (fnc)RNAs are nucleotide sequences of varied lengths, structures, and mechanisms that ubiquitously influence gene expression and translation, genome stability and dynamics, and human health and disease. Here, to shed light on their functional determinants, we seek to exploit the evolutionary record of variation and divergence read from sequence comparisons. The approach follows the phylogenetic Evolutionary Trace (ET) paradigm, first developed and extensively validated on proteins. We assigned a relative rank of importance to every base in a study of 1070 functional RNAs, including the ribosome, and observed evolutionary patterns strikingly similar to those seen in proteins, namely, (1) the top-ranked bases clustered in secondary and tertiary structures. (2) In turn, these clusters mapped functional regions for catalysis, binding proteins and drugs, post-transcriptional modification, and deleterious mutations. (3) Moreover, the quantitative quality of these clusters correlated with the identification of functional regions. (4) As a result of this correlation, smoother structural distributions of evolutionary important nucleotides improved functional site predictions. Thus, in practice, phylogenetic analysis can broadly identify functional determinants in RNA sequences and functional sites in RNA structures, and reveal details on the basis of RNA molecular functions. As example of application, we report several previously undocumented and potentially functional ET nucleotide clusters in the ribosome. This work is broadly relevant to studies of structure-function in ribonucleic acids. Additionally, this generalization of ET shows that evolutionary constraints among sequence, structure, and function are similar in structured RNA and proteins. RNA ET is currently available as part of the ET command-line package, and will be available as a web-server. Traditionally, RNA has been delegated to the role of an intermediate between DNA and proteins. However, we now recognize that RNAs are broadly functional beyond their role in translation, and that a number of diverse classes exist. Because functional, non-coding RNAs are prevalent in biology and impact human health, it is important to better understand their functional determinants. However, the classical solution to this problem, targeted mutagenesis, is time-consuming and scales poorly. We propose an alternative computational approach to this problem, the Evolutionary Trace method. Previously developed and validated for proteins, Evolutionary Trace examines evolutionary history of a molecule and predicts evolutionarily important residues in the sequence. We apply Evolutionary Trace to a set of diverse RNAs, and find that the evolutionarily important nucleotides cluster on the three-dimensional structure, and that these clusters closely overlap functional sites. We also find that the clustering property can be used to refine and improve predictions. These findings are in close agreement with our observations of Evolutionary Trace in proteins, and suggest that structured functional RNAs and proteins evolve under similar constraints. In practice, the approach is to be used by RNA researches seeking insight into their molecule of interest, and the Evolutionary Trace program, along with a working example, is available at https://github.com/LichtargeLab/RNA_ET_ms.
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Affiliation(s)
- Ilya B. Novikov
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Angela D. Wilkins
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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10
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Teplova M, Falschlunger C, Krasheninina O, Egger M, Ren A, Patel DJ, Micura R. Crucial Roles of Two Hydrated Mg
2+
Ions in Reaction Catalysis of the Pistol Ribozyme. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201912522] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Marianna Teplova
- Structural Biology ProgramMemorial Sloan-Kettering Cancer Center New York New York 10065 USA
| | - Christoph Falschlunger
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens University Innrain 80–82 6020 Innsbruck Austria
| | - Olga Krasheninina
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens University Innrain 80–82 6020 Innsbruck Austria
| | - Michaela Egger
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens University Innrain 80–82 6020 Innsbruck Austria
| | - Aiming Ren
- Life Sciences InstituteZhejiang University Hangzhou Zhejiang 310058 China
| | - Dinshaw J. Patel
- Structural Biology ProgramMemorial Sloan-Kettering Cancer Center New York New York 10065 USA
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens University Innrain 80–82 6020 Innsbruck Austria
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11
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Teplova M, Falschlunger C, Krasheninina O, Egger M, Ren A, Patel DJ, Micura R. Crucial Roles of Two Hydrated Mg 2+ Ions in Reaction Catalysis of the Pistol Ribozyme. Angew Chem Int Ed Engl 2020; 59:2837-2843. [PMID: 31804735 PMCID: PMC7027511 DOI: 10.1002/anie.201912522] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Indexed: 12/19/2022]
Abstract
Pistol ribozymes constitute a new class of small self‐cleaving RNAs. Crystal structures have been solved, providing three‐dimensional snapshots along the reaction coordinate of pistol phosphodiester cleavage, corresponding to the pre‐catalytic state, a vanadate mimic of the transition state, and the product. The results led to the proposed underlying chemical mechanism. Importantly, a hydrated Mg2+ ion remains innersphere‐coordinated to N7 of G33 in all three states, and is consistent with its likely role as acid in general acid base catalysis (δ and β catalysis). Strikingly, the new structures shed light on a second hydrated Mg2+ ion that approaches the scissile phosphate from its binding site in the pre‐cleavage state to reach out for water‐mediated hydrogen bonding in the cyclophosphate product. The major role of the second Mg2+ ion appears to be the stabilization of product conformation. This study delivers a mechanistic understanding of ribozyme‐catalyzed backbone cleavage.
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Affiliation(s)
- Marianna Teplova
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, 10065, USA
| | - Christoph Falschlunger
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens University, Innrain 80-82, 6020, Innsbruck, Austria
| | - Olga Krasheninina
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens University, Innrain 80-82, 6020, Innsbruck, Austria
| | - Michaela Egger
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens University, Innrain 80-82, 6020, Innsbruck, Austria
| | - Aiming Ren
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, 10065, USA
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens University, Innrain 80-82, 6020, Innsbruck, Austria
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12
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Maurel MC, Leclerc F, Hervé G. Ribozyme Chemistry: To Be or Not To Be under High Pressure. Chem Rev 2019; 120:4898-4918. [DOI: 10.1021/acs.chemrev.9b00457] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marie-Christine Maurel
- Institut de Systématique, Evolution, Biodiversité (ISYEB), CNRS, Sorbonne Université, Muséum National d’Histoire Naturelle, EPHE, F-75005 Paris, France
| | - Fabrice Leclerc
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Guy Hervé
- Laboratoire BIOSIPE, Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Campus Pierre et Marie Curie, F-75005 Paris, France
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13
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Mao S, Ranganathan SV, Tsai HC, Haruehanroengra P, Shen F, Valsangkar VA, Han B, Hassan AEA, Chen A, Sheng J. Cyano Modification on Uridine Decreases Base-Pairing Stability and Specificity through Neighboring Disruption in RNA Duplex. Chembiochem 2018; 19:2558-2565. [PMID: 30294879 DOI: 10.1002/cbic.201800399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/21/2018] [Indexed: 12/20/2022]
Abstract
5-Cyanomethyluridine (cnm5 U) and 5-cyanouridine (cn5 U), the two uridine analogues, were synthesized and incorporated into RNA oligonucleotides. Base-pairing stability and specificity studies in RNA duplexes indicated that cnm5 U slightly decreased the stability of the duplex but retained the base-pairing preference. In contrast, cn5 U dramatically decreased both base-pairing stability and specificity between U:A and other noncanonical U:G, U:U, and U:C pairs. In addition, the cn5 U:G pair was found to be stronger than the cn5 U:A pair and the other mismatched pairs in the context of a RNA duplex; this implied that cn5 U might slightly prefer to recognize G over A. Our mechanistic studies by molecular simulations showed that the cn5 U modification did not directly affect the base pairing of the parent nucleotide; instead, it weakened the neighboring base pair in the 5' side of the modification in the RNA duplexes. Consistent with the simulation data, replacing the Watson-Crick A:U pair to a mismatched C:U pair in the 5'-neighboring site did not affect the overall stability of the duplex. Our work reveals the significance of the electron-withdrawing cyano group in natural tRNA systems and provides two novel building blocks for constructing RNA-based therapeutics.
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Affiliation(s)
- Song Mao
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Srivathsan V Ranganathan
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Hsu-Chun Tsai
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Phensinee Haruehanroengra
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Fusheng Shen
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Vibhav A Valsangkar
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Bo Han
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Abdalla E A Hassan
- Applied Nucleic Acids Research Center, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Alan Chen
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Jia Sheng
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
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14
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Acosta-Silva C, Bertran J, Branchadell V, Oliva A. Phosphoryl-Transfer Reaction in RNA under Alkaline Conditions. Chemistry 2018; 24:13565-13572. [PMID: 29943454 DOI: 10.1002/chem.201802332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/20/2018] [Indexed: 11/09/2022]
Abstract
The phosphoryl-transfer reaction in RNA under alkaline conditions by exploring the influence of several solvents theoretically was studied. The calculations were carried out by using the M06-2X functional and the solvents were taken as a continuum by using the solvent model density (SMD) method. The main findings show that the O2'-P-O5' angle in the reactants, the free activation energies, and the reaction mechanism are clearly dependent on the dielectric constant of the environment, thus showing that the electrostatic term is the determining factor for this chemical system with two negative charges. Our study seems to indicate that water, the solvent with the greatest dielectric constant, would be the solvent that increases the reaction rate the most. As this outcome was not the case in enzymatic catalysis, one has to conclude that, in the case of proteins as well as for ribozymes, the enzymatic catalysis is not mainly due to the solvent reaction field, but to local electrical fields as a result of enzyme preorganization.
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Affiliation(s)
- Carles Acosta-Silva
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Joan Bertran
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Vicenç Branchadell
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Antoni Oliva
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
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15
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Šponer J, Bussi G, Krepl M, Banáš P, Bottaro S, Cunha RA, Gil-Ley A, Pinamonti G, Poblete S, Jurečka P, Walter NG, Otyepka M. RNA Structural Dynamics As Captured by Molecular Simulations: A Comprehensive Overview. Chem Rev 2018; 118:4177-4338. [PMID: 29297679 PMCID: PMC5920944 DOI: 10.1021/acs.chemrev.7b00427] [Citation(s) in RCA: 336] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 12/14/2022]
Abstract
With both catalytic and genetic functions, ribonucleic acid (RNA) is perhaps the most pluripotent chemical species in molecular biology, and its functions are intimately linked to its structure and dynamics. Computer simulations, and in particular atomistic molecular dynamics (MD), allow structural dynamics of biomolecular systems to be investigated with unprecedented temporal and spatial resolution. We here provide a comprehensive overview of the fast-developing field of MD simulations of RNA molecules. We begin with an in-depth, evaluatory coverage of the most fundamental methodological challenges that set the basis for the future development of the field, in particular, the current developments and inherent physical limitations of the atomistic force fields and the recent advances in a broad spectrum of enhanced sampling methods. We also survey the closely related field of coarse-grained modeling of RNA systems. After dealing with the methodological aspects, we provide an exhaustive overview of the available RNA simulation literature, ranging from studies of the smallest RNA oligonucleotides to investigations of the entire ribosome. Our review encompasses tetranucleotides, tetraloops, a number of small RNA motifs, A-helix RNA, kissing-loop complexes, the TAR RNA element, the decoding center and other important regions of the ribosome, as well as assorted others systems. Extended sections are devoted to RNA-ion interactions, ribozymes, riboswitches, and protein/RNA complexes. Our overview is written for as broad of an audience as possible, aiming to provide a much-needed interdisciplinary bridge between computation and experiment, together with a perspective on the future of the field.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Sandro Bottaro
- Structural Biology and NMR Laboratory, Department of Biology , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Richard A Cunha
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Alejandro Gil-Ley
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Giovanni Pinamonti
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Simón Poblete
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
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16
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Aboelnga MM, Hayward JJ, Gauld JW. Unraveling the Critical Role Played by Ado762'OH in the Post-Transfer Editing by Archaeal Threonyl-tRNA Synthetase. J Phys Chem B 2018; 122:1092-1101. [PMID: 29281289 DOI: 10.1021/acs.jpcb.7b10254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Archaeal threonyl-tRNA synthetase (ThrRS) possesses an editing active site wherein tRNAThr that has been misaminoacylated with serine (i.e., Ser-tRNAThr) is hydrolytically cleaved to serine and tRNAThr. It has been suggested that the free ribose sugar hydroxyl of Ado76 of the tRNAThr (Ado762'OH) is the mechanistic base, promoting hydrolysis by orienting a nucleophilic water near the scissile Ser-tRNAThr ester bond. We have performed a computational study, involving molecular dynamics (MD) and hybrid ONIOM quantum mechanics/molecular mechanics (QM/MM) methods, considering all possible editing mechanisms to gain an understanding of the role played by Ado762'OH group. More specifically, a range of concerted or stepwise mechanisms involving four-, six-, or eight-membered transition structures (total of seven mechanisms) were considered. In addition, these seven mechanisms were fully optimized using three different DFT functionals, namely, B3LYP, M06-2X, and M06-HF. The M06-HF functional gave the most feasible energy barriers followed by the M06-2X functional. The most favorable mechanism proceeds stepwise through two six-membered ring transition states in which the Ado762'OH group participates, overall, as a shuttle for the proton transfer from the nucleophilic H2O to the bridging oxygen (Ado763'O) of the substrate. More specifically, in the first step, which has a barrier of 25.9 kcal/mol, the Ado762'-OH group accepts a proton from the attacking nucleophilic water while concomitantly transferring its proton onto the substrates C-Ocarb center. Then, in the second step, which also proceeds with a barrier of 25.9 kcal/mol, the Ado762'-OH group transfers its proton on the adjacent Ado763'-oxygen, cleaving the scissile Ccarb-O3'Ado76 bond, while concomitantly accepting a proton from the previously formed C-OcarbH group.
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Affiliation(s)
- Mohamed M Aboelnga
- Department of Chemistry and Biochemistry, University of Windsor , Windsor, Ontario N9B 3P4, Canada.,Department of Chemistry, Faculty of Science, Damietta University , New Damietta, Damietta Governorate 34511, Egypt
| | - John J Hayward
- Department of Chemistry and Biochemistry, University of Windsor , Windsor, Ontario N9B 3P4, Canada
| | - James W Gauld
- Department of Chemistry and Biochemistry, University of Windsor , Windsor, Ontario N9B 3P4, Canada
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17
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Wang TP, Su YC, Chen Y, Severance S, Hwang CC, Liou YM, Lu CH, Lin KL, Zhu RJ, Wang EC. Corroboration of Zn( ii)–Mg( ii)-tertiary structure interplays essential for the optimal catalysis of a phosphorothiolate thiolesterase ribozyme. RSC Adv 2018; 8:32775-32793. [PMID: 35547718 PMCID: PMC9086351 DOI: 10.1039/c8ra05083j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/06/2018] [Indexed: 11/21/2022] Open
Abstract
The TW17 ribozyme, a catalytic RNA selected from a pool of artificial RNA, is specific for the Zn2+-dependent hydrolysis of a phosphorothiolate thiolester bond. Here, we describe the organic synthesis of both guanosine α-thio-monophosphate and the substrates required for selecting and characterizing the TW17 ribozyme, and for deciphering the catalytic mechanism of the ribozyme. By successively substituting the substrate originally conjugated to the RNA pool with structurally modified substrates, we demonstrated that the TW17 ribozyme specifically catalyzes phosphorothiolate thiolester hydrolysis. Metal titration studies of TW17 ribozyme catalysis in the presence of Zn2+ alone, Zn2+ and Mg2+, and Zn2+ and [Co(NH3)6]3+ supported our findings that Zn2+ is absolutely required for ribozyme catalysis, and indicated that optimal ribozyme catalysis involves the presence of outer-sphere and one inner-sphere Mg2+. A survey of the TW17 ribozyme activity at various pHs revealed that the activity of the ribozyme critically depends on the alkaline conditions. Moreover, a GNRA tetraloop-containing ribozyme constructed with active catalysis in trans provided catalysis and multiple substrate turnover efficiencies significantly higher than ribozymes lacking a GNRA tetraloop. This research supports the essential roles of Zn2+, Mg2+, and a GNRA tetraloop in modulating the TW17 ribozyme structure for optimal ribozyme catalysis, leading also to the formulation of a proposed reaction mechanism for TW17 ribozyme catalysis. Zn(ii) and Mg(ii) and GAGA tetraloop in the ion atmosphere of the TW17 ribozyme is critical to optimal ribozyme catalysis at alkaline pH.![]()
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Affiliation(s)
- Tzu-Pin Wang
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
- Kaohsiung Medical University Hospital
| | - Yu-Chih Su
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Yi Chen
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Scott Severance
- Department of Molecular and Cellular Sciences
- Liberty University College of Osteopathic Medicine
- Lynchburg
- USA
| | - Chi-Ching Hwang
- Department of Biochemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Yi-Ming Liou
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Chia-Hui Lu
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Kun-Liang Lin
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Rui Jing Zhu
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
| | - Eng-Chi Wang
- Department of Medicinal and Applied Chemistry
- Kaohsiung Medical University
- Kaohsiung
- Taiwan
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18
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Mlýnský V, Kührová P, Jurečka P, Šponer J, Otyepka M, Banáš P. Mapping the Chemical Space of the RNA Cleavage and Its Implications for Ribozyme Catalysis. J Phys Chem B 2017; 121:10828-10840. [DOI: 10.1021/acs.jpcb.7b09129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vojtěch Mlýnský
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), via
Bonomea 265, 34136 Trieste, Italy
| | - Petra Kührová
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Petr Jurečka
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Jiří Šponer
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, 612 65 Brno, Czech Republic
| | - Michal Otyepka
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Pavel Banáš
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, 612 65 Brno, Czech Republic
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19
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Acosta-Silva C, Bertran J, Branchadell V, Oliva A. Phosphoryl Transfer Reaction in RNA: Is the Substrate-Assisted Catalysis a Possible Mechanism in Certain Solvents? J Phys Chem A 2017; 121:8525-8534. [PMID: 29039953 DOI: 10.1021/acs.jpca.7b09156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A proton shuttle mechanism for the phosphoryl transfer reaction in RNA, in which a proton is transferred from the nucleophile to the leaving group through a nonbridged oxygen atom of the phosphate, was explored using the MO6-2X density functional method and the solvent continuum model. This reaction is the initial step of the RNA hydrolysis. We used different solvents characterized by their dielectric constant, and, for each of them, we studied the nuclear and electronic relaxation, produced by the solvent reaction field, for the stationary points. Given that RNA has a poor leaving group, the bond breaking corresponds to the rate-determining step. If the O atom is substituted by a S atom, the leaving group is now good, and the rate-determining step is now the nucleophilic attack concerted with the proton transfer. The most relevant result we found is that none of the solvents we studied has a free energy of activation that is smaller than the one in water. This suggests that the enzyme catalysis following this mechanism must be due to the permanent electric field that is created by a preorganized charge distribution but not to the solvent reaction field.
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Affiliation(s)
- Carles Acosta-Silva
- Department of Chemistry, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
| | - Joan Bertran
- Department of Chemistry, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
| | - Vicenç Branchadell
- Department of Chemistry, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
| | - Antoni Oliva
- Department of Chemistry, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
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20
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Passalacqua LFM, Jimenez RM, Fong JY, Lupták A. Allosteric Modulation of the Faecalibacterium prausnitzii Hepatitis Delta Virus-like Ribozyme by Glucosamine 6-Phosphate: The Substrate of the Adjacent Gene Product. Biochemistry 2017; 56:6006-6014. [PMID: 29045794 DOI: 10.1021/acs.biochem.7b00879] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Self-cleaving ribozymes were discovered 30 years ago and have been found throughout nature, from bacteria to animals, but little is known about their biological functions and regulation, particularly how cofactors and metabolites alter their activity. A hepatitis delta virus-like self-cleaving ribozyme maps upstream of a phosphoglucosamine mutase (glmM) open reading frame in the genome of the human gut bacterium Faecalibacterium prausnitzii. The presence of a ribozyme in the untranslated region of glmM suggests a regulation mechanism of gene expression. In the bacterial hexosamine biosynthesis pathway, the enzyme glmM catalyzes the isomerization of glucosamine 6-phosphate into glucosamine 1-phosphate. In this study, we investigated the effect of these metabolites on the co-transcriptional self-cleavage rate of the ribozyme. Our results suggest that glucosamine 6-phosphate, but not glucosamine 1-phosphate, is an allosteric ligand that increases the self-cleavage rate of drz-Fpra-1, providing the first known example of allosteric modulation of a self-cleaving ribozyme by the substrate of the adjacent gene product. Given that the ribozyme is activated by the glmM substrate, but not the product, this allosteric modulation may represent a potential feed-forward mechanism of gene expression regulation in bacteria.
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Affiliation(s)
- Luiz F M Passalacqua
- Department of Pharmaceutical Sciences, University of California , Irvine, California 92697, United States
| | - Randi M Jimenez
- Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697, United States
| | - Jennifer Y Fong
- Department of Pharmaceutical Sciences, University of California , Irvine, California 92697, United States
| | - Andrej Lupták
- Department of Pharmaceutical Sciences, University of California , Irvine, California 92697, United States.,Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697, United States.,Department of Chemistry, University of California , Irvine, California 92697, United States
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21
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White NA, Hoogstraten CG. Thermodynamics and kinetics of RNA tertiary structure formation in the junctionless hairpin ribozyme. Biophys Chem 2017; 228:62-68. [PMID: 28710920 PMCID: PMC5572644 DOI: 10.1016/j.bpc.2017.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/24/2017] [Accepted: 07/02/2017] [Indexed: 11/15/2022]
Abstract
The hairpin ribozyme consists of two RNA internal loops that interact to form the catalytically active structure. This docking transition is a rare example of intermolecular formation of RNA tertiary structure without coupling to helix annealing. We have used temperature-dependent surface plasmon resonance (SPR) to characterize the thermodynamics and kinetics of RNA tertiary structure formation for the junctionless form of the ribozyme, in which loops A and B reside on separate molecules. We find docking to be strongly enthalpy-driven and to be accompanied by substantial activation barriers for association and dissociation, consistent with the structural reorganization of both internal loops upon complex formation. Comparisons with the parallel analysis of a ribozyme variant carrying a 2'-O-methyl modification at the self-cleavage site and with published data in other systems reveal a surprising diversity of thermodynamic signatures, emphasizing the delicate balance of contributions to the free energy of formation of RNA tertiary structure.
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Affiliation(s)
- Neil A White
- Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 302D, Michigan State University, East Lansing, MI 48824, USA
| | - Charles G Hoogstraten
- Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 302D, Michigan State University, East Lansing, MI 48824, USA.
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22
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Ochieng PO, White NA, Feig M, Hoogstraten CG. Intrinsic Base-Pair Rearrangement in the Hairpin Ribozyme Directs RNA Conformational Sampling and Tertiary Interface Formation. J Phys Chem B 2016; 120:10885-10898. [PMID: 27701852 DOI: 10.1021/acs.jpcb.6b05606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dynamic fluctuations in RNA structure enable conformational changes that are required for catalysis and recognition. In the hairpin ribozyme, the catalytically active structure is formed as an intricate tertiary interface between two RNA internal loops. Substantial alterations in the structure of each loop are observed upon interface formation, or docking. The very slow on-rate for this relatively tight interaction has led us to hypothesize a double conformational capture mechanism for RNA-RNA recognition. We used extensive molecular dynamics simulations to assess conformational sampling in the undocked form of the loop domain containing the scissile phosphate (loop A). We observed several major accessible conformations with distinctive patterns of hydrogen bonding and base stacking interactions in the active-site internal loop. Several important conformational features characteristic of the docked state were observed in well-populated substates, consistent with the kinetic sampling of docking-competent states by isolated loop A. Our observations suggest a hybrid or multistage binding mechanism, in which initial conformational selection of a docking-competent state is followed by induced-fit adjustment to an in-line, chemically reactive state only after formation of the initial complex with loop B.
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Affiliation(s)
- Patrick O Ochieng
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Neil A White
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Charles G Hoogstraten
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
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23
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Wang R, Ranganathan SV, Basanta-Sanchez M, Shen F, Chen A, Sheng J. Synthesis and base pairing studies of geranylated 2-thiothymidine, a natural variant of thymidine. Chem Commun (Camb) 2016; 51:16369-72. [PMID: 26405057 DOI: 10.1039/c5cc07479g] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The synthesis and base pairing of DNA duplexes containing the geranylated 2-thiothymidine have been investigated. This naturally existing hydrophobic modification could grant better base pairing stability to the T-G pair over normal T-A and other mismatched pairs in the duplex context. This study provides a potential explanation for the different codon recognition preferences of the geranylated tRNAs.
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Affiliation(s)
- Rui Wang
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA. and The RNA Institute, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA
| | - Srivathsan V Ranganathan
- The RNA Institute, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA
| | - Maria Basanta-Sanchez
- The RNA Institute, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA
| | - Fusheng Shen
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA. and The RNA Institute, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA
| | - Alan Chen
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA. and The RNA Institute, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA
| | - Jia Sheng
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA. and The RNA Institute, University at Albany, State University of New York, 1400 Washington Ave. Albany, NY 12222, USA
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24
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Chakraborty K, Khatua P, Bandyopadhyay S. Exploring ion induced folding of a single-stranded DNA oligomer from molecular simulation studies. Phys Chem Chem Phys 2016; 18:15899-910. [PMID: 27241311 DOI: 10.1039/c6cp00663a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
One crucial issue in DNA hydration is the effect of salts on its conformational features. This has relevance in biology as cations present in the cellular environment shield the negative charges on the DNA backbone, thereby reducing the repulsive force between them. By screening the negative charges along the backbone, cations stabilize the folded structure of DNA. To study the effect of the added salt on single-stranded DNA (ss-DNA) conformations, we have performed room temperature molecular dynamics simulations of an aqueous solution containing the ss-DNA dodecamer with the 5'-CGCGAATTCGCG-3' sequence in the presence of 0.2, 0.5, and 0.8 M NaCl. Our calculations reveal that in the presence of the salt, the DNA molecule forms more collapsed coil-like conformations due to the screening of negative charges along the backbone. Additionally, we demonstrated that the formation of an octahedral inner-sphere complex by the strongly bound ion plays an important role in the stabilization of such folded conformation of DNA. Importantly, it is found that ion-DNA interactions can also explain the formation of non-sequential base stackings with longer lifetimes. Such non-sequential base stackings further stabilize the collapsed coil-like folded form of the DNA oligomer.
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Affiliation(s)
- Kaushik Chakraborty
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302, India.
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25
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Wang R, Luo Z, He K, Delaney MO, Chen D, Sheng J. Base pairing and structural insights into the 5-formylcytosine in RNA duplex. Nucleic Acids Res 2016; 44:4968-77. [PMID: 27079978 PMCID: PMC4889945 DOI: 10.1093/nar/gkw235] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/24/2016] [Indexed: 12/20/2022] Open
Abstract
5-Formylcytidine (f5C), a previously discovered natural nucleotide in the mitochondrial tRNA of many species including human, has been recently detected as the oxidative product of 5-methylcytidine (m5C) through 5-hydroxymethylcytidine (hm5C) in total RNA of mammalian cells. The discovery indicated that these cytosine derivatives in RNA might also play important epigenetic roles similar as in DNA, which has been intensively investigated in the past few years. In this paper, we studied the base pairing specificity of f5C in different RNA duplex contexts. We found that the 5-formyl group could increase duplex thermal stability and enhance base pairing specificity. We present three high-resolution crystal structures of an octamer RNA duplex [5′-GUA(f5C)GUAC-3′]2 that have been solved under three crystallization conditions with different buffers and pH values. Our results showed that the 5-formyl group is located in the same plane as the cytosine base and forms an intra-residue hydrogen bond with the amino group in the N4 position. In addition, this modification increases the base stacking between the f5C and the neighboring bases while not causing significant global and local structure perturbations. This work provides insights into the effects of 5-formylcytosine on RNA duplex.
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Affiliation(s)
- Rui Wang
- Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Zhipu Luo
- Synchrotron Radiation Research Section, MCL National Cancer Institute, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Kaizhang He
- Dharmacon, GE Healthcare, Lafayette, CO 80026, USA
| | | | - Doris Chen
- Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jia Sheng
- Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
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26
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Gaines CS, York DM. Ribozyme Catalysis with a Twist: Active State of the Twister Ribozyme in Solution Predicted from Molecular Simulation. J Am Chem Soc 2016; 138:3058-65. [PMID: 26859432 PMCID: PMC4904722 DOI: 10.1021/jacs.5b12061] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We present results from molecular dynamics simulations and free energy calculations of the twister ribozyme at different stages along the reaction path to gain insight into its mechanism. The results, together with recent biochemical experiments, provide support for a mechanism involving general-acid catalysis by a conserved adenine residue in the active site. Although adenine has been previously implicated as a general acid acting through the N1 position in other ribozymes such as the hairpin and VS ribozymes, in the twister ribozyme there may be a twist. Biochemical experiments suggest that general acid catalysis may occur through the N3 position, which has never before been implicated in this role; however, currently, there is a lack of a detailed structural model for the active state of the twister ribozyme in solution that is consistent with these and other experiments. Simulations in a crystalline environment reported here are consistent with X-ray crystallographic data, and suggest that crystal packing contacts trap the RNA in an inactive conformation with U-1 in an extruded state that is incompatible with an in-line attack to the scissile phosphate. Simulations in solution, on the other hand, reveal this region to be dynamic and able to adopt a conformation where U-1 is stacked with G33. In this state, the nucleophile is in line with the scissile phosphate, and the N1 position of G33 and N3 position of A1 are poised to act as a general base and acid, respectively, as supported by mutational experiments. Free energy calculations further predict the electrostatic environment causes a shift of the microscopic pKa at the N3 position of A1 toward neutrality by approximately 5 pKa units. These results offer a unified interpretation of a broad range of currently available experimental data that points to a novel mode of general acid catalysis through the N3 position of an adenine nucleobase, thus expanding the repertoire of known mechanistic strategies employed by small nucleolytic ribozymes.
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Affiliation(s)
- Colin S. Gaines
- Center for Integrative Proteomics Research and Department of Chemistry & Chemical Biology, Rutgers University, 174 Frelinghuysen Road, Piscataway, NJ 08854-8076, USA
| | - Darrin M. York
- Center for Integrative Proteomics Research and Department of Chemistry & Chemical Biology, Rutgers University, 174 Frelinghuysen Road, Piscataway, NJ 08854-8076, USA
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Ruminski DJ, Watson PY, Mahen EM, Fedor MJ. A DEAD-box RNA helicase promotes thermodynamic equilibration of kinetically trapped RNA structures in vivo. RNA (NEW YORK, N.Y.) 2016; 22:416-27. [PMID: 26759451 PMCID: PMC4748819 DOI: 10.1261/rna.055178.115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/05/2015] [Indexed: 05/24/2023]
Abstract
RNAs must assemble into specific structures in order to carry out their biological functions, but in vitro RNA folding reactions produce multiple misfolded structures that fail to exchange with functional structures on biological time scales. We used carefully designed self-cleaving mRNAs that assemble through well-defined folding pathways to identify factors that differentiate intracellular and in vitro folding reactions. Our previous work showed that simple base-paired RNA helices form and dissociate with the same rate and equilibrium constants in vivo and in vitro. However, exchange between adjacent secondary structures occurs much faster in vivo, enabling RNAs to quickly adopt structures with the lowest free energy. We have now used this approach to probe the effects of an extensively characterized DEAD-box RNA helicase, Mss116p, on a series of well-defined RNA folding steps in yeast. Mss116p overexpression had no detectable effect on helix formation or dissociation kinetics or on the stability of interdomain tertiary interactions, consistent with previous evidence that intracellular factors do not affect these folding parameters. However, Mss116p overexpression did accelerate exchange between adjacent helices. The nonprocessive nature of RNA duplex unwinding by DEAD-box RNA helicases is consistent with a branch migration mechanism in which Mss116p lowers barriers to exchange between otherwise stable helices by the melting and annealing of one or two base pairs at interhelical junctions. These results suggest that the helicase activity of DEAD-box proteins like Mss116p distinguish intracellular RNA folding pathways from nonproductive RNA folding reactions in vitro and allow RNA structures to overcome kinetic barriers to thermodynamic equilibration in vivo.
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Affiliation(s)
- Dana J Ruminski
- Department of Chemical Physiology, Department of Cell and Molecular Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Peter Y Watson
- Department of Chemical Physiology, Department of Cell and Molecular Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Elisabeth M Mahen
- Department of Chemical Physiology, Department of Cell and Molecular Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Martha J Fedor
- Department of Chemical Physiology, Department of Cell and Molecular Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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28
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Ligation of RNA Oligomers by the Schistosoma mansoni Hammerhead Ribozyme in Frozen Solution. J Mol Evol 2016; 82:81-92. [PMID: 26897022 DOI: 10.1007/s00239-016-9729-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 02/10/2016] [Indexed: 01/29/2023]
Abstract
The interstitial liquid phase within frozen aqueous solutions is an environment that minimizes RNA degradation and facilitates reactions that may have relevance to the RNA World hypothesis. Previous work has shown that frozen solutions support condensation of activated nucleotides into RNA oligomers, RNA ligation by the hairpin ribozyme, and RNA synthesis by a RNA polymerase ribozyme. In the current study, we examined the activity of a hammerhead ribozyme (HHR) in frozen solution. The Schistosoma mansoni hammerhead ribozyme, which predominantly cleaves RNA, can ligate its cleaved products (P1 and P2) with yields up to ~23 % in single turnover experiments at 25 °C in the presence of Mg(2+). Our studies show that this HHR ligates RNA oligomers in frozen solution in the absence of divalent cations. Citrate and other anions that exhibit strong ion-water affinity enhanced ligation. Yields up to 43 % were observed in one freeze-thaw cycle and a maximum of 60 % was obtained after several freeze-thaw cycles using wild-type P1 and P2. Truncated and mutated P1 substrates were ligated to P2 with yields of 14-24 % in one freeze-thaw cycle. A pool of P2 substrates with mixtures of all four bases at five positions were ligated with P1 in frozen solution. High-throughput sequencing indicated that 70 of the 1024 possible P2 sequences were represented in ligated products at 1000 or more read counts per million reads. The results indicate that the HHR can ligate a range of short RNA oligomers into an ensemble of diverse sequences in ice.
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29
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Lee TS, Radak BK, Harris ME, York DM. A Two-Metal-Ion-Mediated Conformational Switching Pathway for HDV Ribozyme Activation. ACS Catal 2016; 6:1853-1869. [PMID: 27774349 DOI: 10.1021/acscatal.5b02158] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RNA enzymes serve as a potentially powerful platform from which to design catalysts and engineer new biotechnology. A fundamental understanding of these systems provides insight to guide design. The hepatitis delta virus ribozyme (HDVr) is a small, self-cleaving RNA motif widely distributed in nature, that has served as a paradigm for understanding basic principles of RNA catalysis. Nevertheless, questions remain regarding the precise roles of divalent metal ions and key nucleotides in catalysis. In an effort to establish a reaction mechanism model consistent with available experimental data, we utilize molecular dynamics simulations to explore different conformations and metal ion binding modes along the HDVr reaction path. Building upon recent crystallographic data, our results provide a dynamic model of the HDVr reaction mechanism involving a conformational switch between multiple non-canonical G25:U20 base pair conformations in the active site. These local nucleobase dynamics play an important role in catalysis by modulating the metal binding environments of two Mg2+ ions that support catalysis at different steps of the reaction pathway. The first ion plays a structural role by inducing a base pair flip necessary to obtain the catalytic fold in which C75 moves towards to the scissile phosphate in the active site. Ejection of this ion then permits a second ion to bind elsewhere in the active site and facilitate nucleophile activation. The simulations collectively describe a mechanistic scenario that is consistent with currently available experimental data from crystallography, phosphorothioate substitutions, and chemical probing studies. Avenues for further experimental verification are suggested.
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Affiliation(s)
- Tai-Sung Lee
- Center for Integrative Proteomics Research and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Brian K. Radak
- Center for Integrative Proteomics Research and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
- Argonne National Laboratory, Argonne, Illinois 60439, United State
| | - Michael E. Harris
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, United States
| | - Darrin M. York
- Center for Integrative Proteomics Research and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
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31
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Panteva MT, Giambaşu GM, York DM. Force Field for Mg(2+), Mn(2+), Zn(2+), and Cd(2+) Ions That Have Balanced Interactions with Nucleic Acids. J Phys Chem B 2015; 119:15460-70. [PMID: 26583536 DOI: 10.1021/acs.jpcb.5b10423] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Divalent metal ions are of fundamental importance to the function and folding of nucleic acids. Divalent metal ion-nucleic acid interactions are complex in nature and include both territorial and site specific binding. Commonly employed nonbonded divalent ion models, however, are often parametrized against bulk ion properties and are subsequently utilized in biomolecular simulations without considering any data related to interactions at specific nucleic acid sites. Previously, we assessed the ability of 17 different nonbonded Mg(2+) ion models to reproduce different properties of Mg(2+) in aqueous solution including radial distribution functions, solvation free energies, water exchange rates, and translational diffusion coefficients. In the present work, we depart from the recently developed 12-6-4 potential models for divalent metal ions developed by Li and Merz and tune the pairwise parameters for Mg(2+), Mn(2+), Zn(2+), and Cd(2+) binding dimethyl phosphate, adenosine, and guanosine in order to reproduce experimental site specific binding free energies derived from potentiometric pH titration data. We further apply these parameters to investigate a metal ion migration previously proposed to occur during the catalytic reaction of the hammerhead ribozyme. The new parameters are shown to be accurate and balanced for nucleic acid binding in comparison with available experimental data and provide an important tool for molecular dynamics and free energy simulations of nucleic acids where these ions may exhibit different binding modes.
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Affiliation(s)
- Maria T Panteva
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
| | - George M Giambaşu
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
| | - Darrin M York
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
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32
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Costa Pessoa J, Garribba E, Santos MF, Santos-Silva T. Vanadium and proteins: Uptake, transport, structure, activity and function. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2015.03.016] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Dubecký M, Walter NG, Šponer J, Otyepka M, Banáš P. Chemical feasibility of the general acid/base mechanism of glmS ribozyme self-cleavage. Biopolymers 2015; 103:550-62. [PMID: 25858644 PMCID: PMC4553064 DOI: 10.1002/bip.22657] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/17/2015] [Accepted: 04/02/2015] [Indexed: 01/28/2023]
Abstract
In numerous Gram-positive bacteria, the glmS ribozyme or catalytic riboswitch regulates the expression of glucosamine-6-phosphate (GlcN6P) synthase via site-specific cleavage of its sugar-phosphate backbone in response to GlcN6P ligand binding. Biochemical data have suggested a crucial catalytic role for an active site guanine (G40 in Thermoanaerobacter tengcongensis, G33 in Bacillus anthracis). We used hybrid quantum chemical/molecular mechanical (QM/MM) calculations to probe the mechanism where G40 is deprotonated and acts as a general base. The calculations suggest that the deprotonated guanine G40(-) is sufficiently reactive to overcome the thermodynamic penalty arising from its rare protonation state, and thus is able to activate the A-1(2'-OH) group toward nucleophilic attack on the adjacent backbone. Furthermore, deprotonation of A-1(2'-OH) and nucleophilic attack are predicted to occur as separate steps, where activation of A-1(2'-OH) precedes nucleophilic attack. Conversely, the transition state associated with the rate-determining step corresponds to concurrent nucleophilic attack and protonation of the G1(O5') leaving group by the ammonium moiety of the GlcN6P cofactor. Overall, our calculations help to explain the crucial roles of G40 (as a general base) and GlcN6P (as a general acid) during glmS ribozyme self-cleavage. In addition, we show that the QM/MM description of the glmS ribozyme self-cleavage reaction is significantly more sensitive to the size of the QM region and the quality of the QM-MM coupling than that of other small ribozymes.
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Affiliation(s)
- Matúš Dubecký
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Nils G. Walter
- Department of Chemistry, Single Molecule Analysis Group, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
- CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
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34
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Radak BK, Lee TS, Harris ME, York DM. Assessment of metal-assisted nucleophile activation in the hepatitis delta virus ribozyme from molecular simulation and 3D-RISM. RNA (NEW YORK, N.Y.) 2015; 21:1566-1577. [PMID: 26170378 PMCID: PMC4536318 DOI: 10.1261/rna.051466.115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/26/2015] [Indexed: 06/04/2023]
Abstract
The hepatitis delta virus ribozyme is an efficient catalyst of RNA 2'-O-transphosphorylation and has emerged as a key experimental system for identifying and characterizing fundamental features of RNA catalysis. Recent structural and biochemical data have led to a proposed mechanistic model whereby an active site Mg(2+) ion facilitates deprotonation of the O2' nucleophile, and a protonated cytosine residue (C75) acts as an acid to donate a proton to the O5' leaving group as noted in a previous study. This model assumes that the active site Mg(2+) ion forms an inner-sphere coordination with the O2' nucleophile and a nonbridging oxygen of the scissile phosphate. These contacts, however, are not fully resolved in the crystal structure, and biochemical data are not able to unambiguously exclude other mechanistic models. In order to explore the feasibility of this model, we exhaustively mapped the free energy surfaces with different active site ion occupancies via quantum mechanical/molecular mechanical (QM/MM) simulations. We further incorporate a three-dimensional reference interaction site model for the solvated ion atmosphere that allows these calculations to consider not only the rate associated with the chemical steps, but also the probability of observing the system in the presumed active state with the Mg(2+) ion bound. The QM/MM results predict that a pathway involving metal-assisted nucleophile activation is feasible based on the rate-controlling transition state barrier departing from the presumed metal-bound active state. However, QM/MM results for a similar pathway in the absence of Mg(2+) are not consistent with experimental data, suggesting that a structural model in which the crystallographically determined Mg(2+) is simply replaced with Na(+) is likely incorrect. It should be emphasized, however, that these results hinge upon the assumption of the validity of the presumed Mg(2+)-bound starting state, which has not yet been definitively verified experimentally, nor explored in depth computationally. Thus, further experimental and theoretical study is needed such that a consensus view of the catalytic mechanism emerges.
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Affiliation(s)
- Brian K Radak
- Center for Integrative Proteomics Research and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8076, USA Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA
| | - Tai-Sung Lee
- Center for Integrative Proteomics Research and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8076, USA
| | - Michael E Harris
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | - Darrin M York
- Center for Integrative Proteomics Research and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8076, USA
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35
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Larsen AT, Fahrenbach AC, Sheng J, Pian J, Szostak JW. Thermodynamic insights into 2-thiouridine-enhanced RNA hybridization. Nucleic Acids Res 2015; 43:7675-87. [PMID: 26240387 PMCID: PMC4652770 DOI: 10.1093/nar/gkv761] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/14/2015] [Indexed: 02/07/2023] Open
Abstract
Nucleobase modifications dramatically alter nucleic acid structure and thermodynamics. 2-thiouridine (s(2)U) is a modified nucleobase found in tRNAs and known to stabilize U:A base pairs and destabilize U:G wobble pairs. The recently reported crystal structures of s(2)U-containing RNA duplexes do not entirely explain the mechanisms responsible for the stabilizing effect of s(2)U or whether this effect is entropic or enthalpic in origin. We present here thermodynamic evaluations of duplex formation using ITC and UV thermal denaturation with RNA duplexes containing internal s(2)U:A and s(2)U:U pairs and their native counterparts. These results indicate that s(2)U stabilizes both duplexes. The stabilizing effect is entropic in origin and likely results from the s(2)U-induced preorganization of the single-stranded RNA prior to hybridization. The same preorganizing effect is likely responsible for structurally resolving the s(2)U:U pair-containing duplex into a single conformation with a well-defined H-bond geometry. We also evaluate the effect of s(2)U on single strand conformation using UV- and CD-monitored thermal denaturation and on nucleoside conformation using (1)H NMR spectroscopy, MD and umbrella sampling. These results provide insights into the effects that nucleobase modification has on RNA structure and thermodynamics and inform efforts toward improving both ribozyme-catalyzed and nonenzymatic RNA copying.
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Affiliation(s)
- Aaron T Larsen
- Howard Hughes Medical Institute, Center for Computational and Integrative Biology, and Department of Molecular Biology, Simches Research Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Albert C Fahrenbach
- Howard Hughes Medical Institute, Center for Computational and Integrative Biology, and Department of Molecular Biology, Simches Research Center, Massachusetts General Hospital, Boston, MA 02114, USA Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Jia Sheng
- University at Albany, State University of New York, Department of Chemistry, The RNA Institute, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Julia Pian
- Howard Hughes Medical Institute, Center for Computational and Integrative Biology, and Department of Molecular Biology, Simches Research Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Center for Computational and Integrative Biology, and Department of Molecular Biology, Simches Research Center, Massachusetts General Hospital, Boston, MA 02114, USA Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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36
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Lain L, Lönnberg H, Lönnberg T. Participation of an additional 4'-hydroxymethyl group in the cleavage and isomerization of ribonucleoside 3'-phosphodiesters. Org Biomol Chem 2015; 13:4737-42. [PMID: 25805021 DOI: 10.1039/c5ob00400d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
4'-(Hydroxymethyl)uridylyl-3',5'-thymidine, an RNA model bearing an extra hydroxymethyl group at the 4'-position of the 3'-linked nucleoside, has been prepared and its cleavage and isomerization reactions studied over a wide pH range (from 0 to 12). Overall, the pH-rate profiles of these reactions were very similar to those of uridylyl-3',5'-uridine (UpU) - only a very modest acceleration was observed under acidic and neutral conditions. Evidently, hydrogen bond assistance by the additional hydroxymethyl function does not play a significant role.
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Affiliation(s)
- Luigi Lain
- Department of Chemistry, University of Turku, Vatselankatu 2, FIN-20014 Turku, Finland.
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37
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Koo SC, Lu J, Li NS, Leung E, Das SR, Harris ME, Piccirilli JA. Transition State Features in the Hepatitis Delta Virus Ribozyme Reaction Revealed by Atomic Perturbations. J Am Chem Soc 2015; 137:8973-82. [PMID: 26125657 PMCID: PMC4758122 DOI: 10.1021/jacs.5b01189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Endonucleolytic ribozymes constitute a class of non-coding RNAs that catalyze single-strand RNA scission. With crystal structures available for all of the known ribozymes, a major challenge involves relating functional data to the physically observed RNA architecture. In the case of the hepatitis delta virus (HDV) ribozyme, there are three high-resolution crystal structures, the product state of the reaction and two precursor variants, with distinct mechanistic implications. Here, we develop new strategies to probe the structure and catalytic mechanism of a ribozyme. First, we use double-mutant cycles to distinguish differences in functional group proximity implicated by the crystal structures. Second, we use a corrected form of the Brønsted equation to assess the functional significance of general acid catalysis in the system. Our results delineate the functional relevance of atomic interactions inferred from structure, and suggest that the HDV ribozyme transition state resembles the cleavage product in the degree of proton transfer to the leaving group.
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Affiliation(s)
- Selene C. Koo
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Jun Lu
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Nan-Sheng Li
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Edward Leung
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Subha R. Das
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Michael E. Harris
- Department of Biochemistry and Center for Proteomics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Joseph A. Piccirilli
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
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38
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Wierzchowski J, Antosiewicz JM, Shugar D. 8-Azapurines as isosteric purine fluorescent probes for nucleic acid and enzymatic research. MOLECULAR BIOSYSTEMS 2015; 10:2756-74. [PMID: 25124808 DOI: 10.1039/c4mb00233d] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The 8-azapurines, and their 7-deaza and 9-deaza congeners, represent a unique class of isosteric (isomorphic) analogues of the natural purines, frequently capable of substituting for the latter in many biochemical processes. Particularly interesting is their propensity to exhibit pH-dependent room-temperature fluorescence in aqueous medium, and in non-polar media. We herein review the physico-chemical properties of this class of compounds, with particular emphasis on the fluorescence emission properties of their neutral and/or ionic species, which has led to their widespread use as fluorescent probes in enzymology, including enzymes involved in purine metabolism, agonists/antagonists of adenosine receptors, mechanisms of catalytic RNAs, RNA editing, etc. They are also exceptionally useful fluorescent probes for analytical and clinical applications in crude cell homogenates.
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Affiliation(s)
- Jacek Wierzchowski
- Department of Biophysics, University of Varmia & Masuria, Oczapowskiego 4, 10-719 Olsztyn, Poland.
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39
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Dong X, Tian Z, Yang X, Xue Y. Theoretical study on the mechanism of self-cleavage reaction of the glmS ribozyme. Theor Chem Acc 2015. [DOI: 10.1007/s00214-015-1667-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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40
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Mlýnský V, Kührová P, Zgarbová M, Jurečka P, Walter NG, Otyepka M, Šponer J, Banáš P. Reactive Conformation of the Active Site in the Hairpin Ribozyme Achieved by Molecular Dynamics Simulations with ε/ζ Force Field Reparametrizations. J Phys Chem B 2015; 119:4220-9. [DOI: 10.1021/jp512069n] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Vojtěch Mlýnský
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Petra Kührová
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Marie Zgarbová
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Petr Jurečka
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Nils G. Walter
- Department
of Chemistry, Single Molecule Analysis Group, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Michal Otyepka
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Jiří Šponer
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
- CEITEC
− Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Pavel Banáš
- Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
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Panteva MT, Dissanayake T, Chen H, Radak BK, Kuechler ER, Giambaşu GM, Lee TS, York DM. Multiscale methods for computational RNA enzymology. Methods Enzymol 2015; 553:335-74. [PMID: 25726472 PMCID: PMC4739856 DOI: 10.1016/bs.mie.2014.10.064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RNA catalysis is of fundamental importance to biology and yet remains ill-understood due to its complex nature. The multidimensional "problem space" of RNA catalysis includes both local and global conformational rearrangements, changes in the ion atmosphere around nucleic acids and metal ion binding, dependence on potentially correlated protonation states of key residues, and bond breaking/forming in the chemical steps of the reaction. The goal of this chapter is to summarize and apply multiscale modeling methods in an effort to target the different parts of the RNA catalysis problem space while also addressing the limitations and pitfalls of these methods. Classical molecular dynamics simulations, reference interaction site model calculations, constant pH molecular dynamics (CpHMD) simulations, Hamiltonian replica exchange molecular dynamics, and quantum mechanical/molecular mechanical simulations will be discussed in the context of the study of RNA backbone cleavage transesterification. This reaction is catalyzed by both RNA and protein enzymes, and here we examine the different mechanistic strategies taken by the hepatitis delta virus ribozyme and RNase A.
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Affiliation(s)
- Maria T Panteva
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Thakshila Dissanayake
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Haoyuan Chen
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Brian K Radak
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Erich R Kuechler
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - George M Giambaşu
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Tai-Sung Lee
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Darrin M York
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA.
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Pan F, Roland C, Sagui C. Ion distributions around left- and right-handed DNA and RNA duplexes: a comparative study. Nucleic Acids Res 2014; 42:13981-96. [PMID: 25428372 PMCID: PMC4267617 DOI: 10.1093/nar/gku1107] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/22/2014] [Accepted: 10/23/2014] [Indexed: 12/30/2022] Open
Abstract
The ion atmosphere around nucleic acids is an integral part of their solvated structure. However, detailed aspects of the ionic distribution are difficult to probe experimentally, and comparative studies for different structures of the same sequence are almost non-existent. Here, we have used large-scale molecular dynamics simulations to perform a comparative study of the ion distribution around (5'-CGCGCGCGCGCG-3')2 dodecamers in solution in B-DNA, A-RNA, Z-DNA and Z-RNA forms. The CG sequence is very sensitive to ionic strength and it allows the comparison with the rare but important left-handed forms. The ions investigated include Na(+), K(+) and Mg(2 +), with various concentrations of their chloride salts. Our results quantitatively describe the characteristics of the ionic distributions for different structures at varying ionic strengths, tracing these differences to nucleic acid structure and ion type. Several binding pockets with rather long ion residence times are described, both for the monovalent ions and for the hexahydrated Mg[(H2O)6](2+) ion. The conformations of these binding pockets include direct binding through desolvated ion bridges in the GpC steps in B-DNA and A-RNA; direct binding to backbone oxygens; binding of Mg[(H2O)6](2+) to distant phosphates, resulting in acute bending of A-RNA; tight 'ion traps' in Z-RNA between C-O2 and the C-O2' atoms in GpC steps; and others.
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Affiliation(s)
- Feng Pan
- Center for High Performance Simulations (CHiPS) and Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Christopher Roland
- Center for High Performance Simulations (CHiPS) and Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Celeste Sagui
- Center for High Performance Simulations (CHiPS) and Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
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Abstract
In many synthetic biology applications, modular and easily accessible tools for controlling gene expression are required. In addition, in vivo biosensors and diagnostic devices will become more important in the future to allow for noninvasive determination of protein, ion, or small molecule metabolite levels. In recent years synthetic RNA-based switches have been developed to act as signal transducers to convert a binding event of a small molecule (input) into a detectable output. Their modular design allows the development of a variety of molecular switches to be used in biochemical assays or inside living cells. RNA switches developed by our group are based on the Schistosoma mansoni hammerhead ribozyme, a self-cleaving RNA sequence that can be inserted into any RNA of interest. Connection to an aptamer sensing a small molecule renders the cleavage reaction ligand-dependent. In the past we have successfully designed and applied such hammerhead aptazymes for the allosteric control of both bacterial and eukaryotic gene expression by affecting transcription elongation, translation initiation, or mRNA stability. In order to yield functional switches optimization of the connecting sequence between the aptamer and the HHR needs to be carried out. We have therefore developed an in vivo screening protocol detailed in this chapter that allows the identification of functional aptazymes in bacteria.
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Affiliation(s)
- Charlotte Rehm
- Department of Chemistry, University of Konstanz, Konstanz, Germany
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Sheng J, Larsen A, Heuberger BD, Blain JC, Szostak JW. Crystal structure studies of RNA duplexes containing s(2)U:A and s(2)U:U base pairs. J Am Chem Soc 2014; 136:13916-24. [PMID: 25188906 PMCID: PMC4183603 DOI: 10.1021/ja508015a] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
![]()
Structural studies of modified nucleobases
in RNA duplexes are
critical for developing a full understanding of the stability and
specificity of RNA base pairing. 2-Thio-uridine (s2U) is
a modified nucleobase found in certain tRNAs. Thermodynamic studies
have evaluated the effects of s2U on base pairing in RNA,
where it has been shown to stabilize U:A pairs and destabilize U:G
wobble pairs. Surprisingly, no high-resolution crystal structures
of s2U-containing RNA duplexes have yet been reported.
We present here two high-resolution crystal structures of heptamer
RNA duplexes (5′-uagcs2Ucc-3′ paired with 3′-aucgAgg-5′ and with 3′-aucgUgg-5′) containing s2U:A and s2U:U pairs, respectively. For comparison, we also present the structures
of their native counterparts solved under identical conditions. We
found that replacing O2 with S2 stabilizes the U:A base pair without
any detectable structural perturbation. In contrast, an s2U:U base pair is strongly stabilized in one specific U:U pairing
conformation out of four observed for the native U:U base pair. This
s2U:U stabilization appears to be due at least in part
to an unexpected sulfur-mediated hydrogen bond. This work provides
additional insights into the effects of 2-thio-uridine on RNA base
pairing.
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Affiliation(s)
- Jia Sheng
- Howard Hughes Medical Institute, Center for Computational and Integrative Biology, and Department of Molecular Biology, Simches Research Center, Massachusetts General Hospital , Boston, Massachusetts 02114, United States
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45
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Schultz EP, Vasquez EE, Scott WG. Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid-base catalysis. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:2256-63. [PMID: 25195740 PMCID: PMC4157442 DOI: 10.1107/s1399004714010608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/09/2014] [Indexed: 11/10/2022]
Abstract
The hammerhead ribozyme catalyzes RNA cleavage via acid-base catalysis. Whether it does so by general acid-base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid-base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK(a) of the substituted purine; in both cases inosine, which is similar to G in pK(a) and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the potential role of G12 as a general base, indicates that an alternative hammerhead cleavage mechanism involving specific base catalysis may instead explain the observed rate dependence upon purine substitutions at G12. The crystallographic results, contrary to previous assumptions, therefore cannot be interpreted to favor the general base catalysis mecahnism over the specific base catalysis mechanism. Instead, both of these mutually exclusive mechanistic alternatives must be considered in light of the current structural and biochemical data.
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Affiliation(s)
- Eric P. Schultz
- Department of Chemistry and Biochemistry and The Center for the Molecular Biology of RNA, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | - Ernesto E. Vasquez
- Department of Chemistry and Biochemistry and The Center for the Molecular Biology of RNA, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | - William G. Scott
- Department of Chemistry and Biochemistry and The Center for the Molecular Biology of RNA, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
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Heldenbrand H, Janowski PA, Giambaşu G, Giese TJ, Wedekind JE, York DM. Evidence for the role of active site residues in the hairpin ribozyme from molecular simulations along the reaction path. J Am Chem Soc 2014; 136:7789-92. [PMID: 24842535 PMCID: PMC4132952 DOI: 10.1021/ja500180q] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The hairpin ribozyme accelerates
a phosphoryl transfer reaction
without catalytic participation of divalent metal ions. Residues A38
and G8 have been implicated as playing roles in general acid and base
catalysis, respectively. Here we explore the structure and dynamics
of key active site residues using more than 1 μs of molecular
dynamics simulations of the hairpin ribozyme at different stages along
the catalytic pathway. Analysis of results indicates hydrogen bond
interactions between the nucleophile and proR nonbridging oxygen are
correlated with active inline attack conformations. Further, the simulation
results suggest a possible alternative role for G8 to promote inline
fitness and facilitate activation of the nucleophile by hydrogen bonding,
although this does not necessarily exclude an additional role as a
general base. Finally, we suggest that substitution of G8 with N7-
or N3-deazaguanosine which have elevated pKa values, both with and without thio modifications at the 5′
leaving group position, would provide valuable insight into the specific
role of G8 in catalysis.
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Affiliation(s)
- Hugh Heldenbrand
- Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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Mishra SK, Chilakamarthi U, Deb JK, Mukherjee SK. Unfolding of in planta activity of anti-rep ribozyme in presence of a RNA silencing suppressor. FEBS Lett 2014; 588:1967-72. [PMID: 24735726 PMCID: PMC7164126 DOI: 10.1016/j.febslet.2014.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/03/2014] [Accepted: 04/03/2014] [Indexed: 12/17/2022]
Abstract
Antisense RNA ribozymes have intrinsic endonucleolytic activity to effect cleavage of the target RNA. However, this activity in vivo is often controlled by the dominance of antisense or other double-stranded RNA mechanism. In this work, we demonstrate the in planta activity of a hammerhead ribozyme designed to target rep-mRNA of a phytopathogen Mungbean Yellow Mosaic India virus (MYMIV) as an antiviral agent. We also found RNA-silencing is induced on introduction of catalytically active as well as inactive ribozymes. Using RNA-silencing suppressors (RSS), we demonstrate that the endonucleolytic activity of ribozymes is a true phenomenon, even while a mutated version may demonstrate a similar down-regulation of the target RNA. This helps to ease the confusion over the action mechanism of ribozymes in vivo.
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Affiliation(s)
- Sumona Karjee Mishra
- Plant Molecular Biology Division, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
| | - Ushasri Chilakamarthi
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India
| | - J K Deb
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India
| | - Sunil Kumar Mukherjee
- Plant Molecular Biology Division, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110 067, India; Department of Genetics, University of Delhi, South Campus, Benito Juarez Marg, New Delhi 110021, India
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Ward WL, Plakos K, DeRose VJ. Nucleic acid catalysis: metals, nucleobases, and other cofactors. Chem Rev 2014; 114:4318-42. [PMID: 24730975 PMCID: PMC4002065 DOI: 10.1021/cr400476k] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Indexed: 12/17/2022]
Affiliation(s)
- W. Luke Ward
- Department of Chemistry and Biochemistry and Institute of
Molecular Biology, University of Oregon, Eugene, Oregon 97403, United States
| | - Kory Plakos
- Department of Chemistry and Biochemistry and Institute of
Molecular Biology, University of Oregon, Eugene, Oregon 97403, United States
| | - Victoria J. DeRose
- Department of Chemistry and Biochemistry and Institute of
Molecular Biology, University of Oregon, Eugene, Oregon 97403, United States
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Mlýnský V, Banáš P, Šponer J, van der Kamp MW, Mulholland AJ, Otyepka M. Comparison of ab Initio, DFT, and Semiempirical QM/MM Approaches for Description of Catalytic Mechanism of Hairpin Ribozyme. J Chem Theory Comput 2014; 10:1608-22. [PMID: 26580373 DOI: 10.1021/ct401015e] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We have analyzed the capability of state-of-the-art multiscale computational approaches to provide atomic-resolution electronic structure insights into possible catalytic scenarios of the hairpin ribozyme by evaluating potential and free energy surfaces of the reactions by various hybrid QM/MM methods. The hairpin ribozyme is a unique catalytic RNA that achieves rate acceleration similar to other small self-cleaving ribozymes but without direct metal ion participation. Guanine 8 (G8) and adenine 38 (A38) have been identified as the catalytically essential nucleobases. However, their exact catalytic roles are still being investigated. In line with the available experimental data, we considered two reaction scenarios involving protonated A38H(+) as a general acid which is further assisted by either canonical G8 or deprotonated G8(-) forms. We used the spin-component scaled Møller-Plesset (SCS-MP2) method at the complete basis set limit as the reference method. The semiempirical AM1/d-PhoT and SCC-DFTBPR methods provided acceptable activation barriers with respect to the SCS-MP2 data but predicted significantly different reaction pathways. DFT functionals (BLYP and MPW1K) yielded the same reaction pathway as the SCS-MP2 method. The activation barriers were slightly underestimated by the GGA BLYP functional, although with accuracy comparable to the semiempirical methods. The SCS-MP2 method and hybrid MPW1K functional gave activation barriers that were closest to those derived from experimentally measured rate constants.
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Affiliation(s)
- Vojtěch Mlýnský
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics , Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic
- CEITEC-Central European Institute of Technology, Masaryk University , Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Marc W van der Kamp
- Centre for Computational Chemistry, School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
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50
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Elsässer B, Fels G, Weare JH. QM/MM simulation (B3LYP) of the RNase A cleavage-transesterification reaction supports a triester A(N) + D(N) associative mechanism with an O2' H internal proton transfer. J Am Chem Soc 2014; 136:927-36. [PMID: 24372083 DOI: 10.1021/ja406122c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mechanism of the backbone cleavage-transesterification step of the RNase A enzyme remains controversial even after 60 years of study. We report quantum mechanics/molecule mechanics (QM/MM) free energy calculations for two optimized reaction paths based on an analysis of all structural data and identified by a search for reaction coordinates using a reliable quantum chemistry method (B3LYP), equilibrated structural optimizations, and free energy estimations. Both paths are initiated by nucleophilic attack of the ribose O2' oxygen on the neighboring diester phosphate bond, and both reach the same product state (PS) (a O3'-O2' cyclic phosphate and a O5' hydroxyl terminated fragment). Path 1, resembles the widely accepted dianionic transition-state (TS) general acid (His119)/base (His12) classical mechanism. However, this path has a barrier (25 kcal/mol) higher than that of the rate-limiting hydrolysis step and a very loose TS. In Path 2, the proton initially coordinating the O2' migrates to the nonbridging O1P in the initial reaction path rather than directly to the general base resulting in a triester (substrate as base) AN + DN mechanism with a monoanionic weakly stable intermediate. The structures in the transition region are associative with low barriers (TS1 10, TS2 7.5 kcal/mol). The Path 2 mechanism is consistent with the many results from enzyme and buffer catalyzed and uncatalyzed analog reactions and leads to a PS consistent with the reactive state for the following hydrolysis step. The differences between the consistently estimated barriers in Path 1 and 2 lead to a 10(11) difference in rate strongly supporting the less accepted triester mechanism.
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Affiliation(s)
- Brigitta Elsässer
- Department of Chemistry, University of Paderborn , Warburgerstr. 100, D-33098 Paderborn, Germany
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